Moisture-proofing and moisture-proofed telephone and switchboard cord conductor.



A. PRUESSMAN. MOISTURE YROOFING ANDMOISTURE PHOOFED TBLEPHOEE AND SWITCHBOARD com) CONDUCTOR.

APPLICATION FILED YEB.I6,1912.

1,120,849, Patented Dec. 15, 1914.

2 SHEETS-SHEET 1.

A. PRUESSMAN.

MOISTURE PROOFING AND MOISTURE PROOFED TELEPHONE AND SWITCHBOARD CORD CONDUCTOR.

APPLICATION FILED FEB.16,19X2.

Patented Dec. 15, 1914.

2 SHEET88HEET 2.

/n venfor:

UNTTED STATES PATENT OFFICE.

ALBERT PRUESSMAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPORATIONOF ILLINOIS.

MOISTURE-PROOFING AND MOISTURE-PROOFED TELEPHONE AND SWITCH'BOARD COR-D CONDUCTOR.

Specification of Letters Patent.

Application filed February 16. 1912. Serial No. 678,029.

T 0 all whom it may concern:

Be it known that I, ALBERT PRUESSMAN, citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in hloisture-lroofing and Moisture-Proofed Telephone and Switchboard Cord Conductors,-of which the following is a full, clear, concise, and exact description.

This invention relates to insulated conductors, and more particularly to the application of waterproofing to flexible conducting cords.

The object of the invention is to impart moisture-proof qualities to a fibrous covering of such conductors without impairing the electrical or mechanical eiliciency of the conductor.

It is desirable in the manufacture ot' moistureproof conducting cords that the completed cord shall not show evidence of moistureproofing on the outer braidings as this would affect the appearance of the cord; that it shall not expose any moistureprcofing material as this would tend to interfere with the handling of the cord; that the moistureproofing shall not materially in-. crease the dimensions of the cord and shall not impart its flexibility, nor tend to exert any deteriorating etiect upon materials used, and that the insulation resistance shall be materiallv improved, particularly when the cord is used in humid atmosphere.

In accordance with this invention, the conductor, which may be a plurality of assembled tinsel strands, is first covered with one or more layers of fibrous insulating material. The conductor thus covered is drawn through a heated insulating compound at a rate of progression permitting saturation of the outer portion of the fibrous covering but without permitting penetration sullicient to coat the conductor itself or saturate the strands thereof. Preferably, the fibrous covering consists of two independent helical layers reverselv wound, and the conductor is passed through the insulating compound at such speed that the outer layer is completelv and the inner layer but partially saturated. A blast of cold air may be applied to the conductor after it emerges from the tank and before it is wound on the reel, in order to cool the r-mnpound and pre able tank with means for advancing the conductor and for heating the insulating compound Fig. '2 is a continuation of the view shown in Fig. 1 and includes a. winding reel Patented Dec. 15,1914.

and a polishing die; Fig. 3,-is a sectional" view of a flexible conducting cord; and Fig. 4 is a view of a finished, fiexible,;conducting cord, such as is used in the telephone service. 1

The tank t is suppliedjwithawaterproofing compound whichnia'y'con'sistiof" tum 91%. resin 6%, and resin 0i l -3% compound in the tank is heated asunifd as possible by gas 'jetslirj' N 5 i the tank there is. 0

screen 8, the object come in contact with the i There is a reel 1 rotatably mp or'oed anaxle a;

a friction brake d is applied'to the axle to sphalt anb aa foreign matter to appear in the quid material or to I of strands of tinsel shown at 10 in Fig. 3; on i this is a braiding of tinsel strands 11, and on this are one or more layers 12, 13, of re versely wound fibrous insulating material. such as silk or wool. The moisture-proof insulating material is represented at 14. This permeates the layers 13 and just enters the layer 12- without coming in contact with the conductor 10, 11. Outside the moistureproof material 14, applied as described, is a finishing covering of braided insulating material like 15.

The temperature of the compound in the tank t should be maintained at from 390 to 420 Fahrenheit. The compound is heated to a minimum working temperature of 390 Fahrenheit in order that it may be thinned to a point necessary for properly impregnating the conductor, and is kept from exceeding a maximum of 420 Fahrenheit to avoid inj uring the conductor by overheating. A good specimen of conductor is insulated with double tussah floss, or with single worsted; such a conductor is passed through the tank in six lengths or passes, immersing from sixteen to twent four feet of conductor inthe compound. it requires one minute to properly impregnate the.

double'tussah floss insulated conductor and fifteen seconds to insulate the wool covered conductor. Under these conditions the comparative outputs are respectively 1440 feet per hour for the tussah floss and 3840 feet per hour for the wool insulated conductor. The insulating compound, when the conductor is passed through the tank at the rate of 3840 feet per hour, will cool, underordinary conditions, within a distance' of twelve feet after leaving the tank; but as it is desirable to cool it as quickly as ossible in order to prevent the turns of t e conductor from sticking together, a blast of cold air should be applied to the conductor by some suitable lating compound at a rate of progression permitting saturation of said outer layer and of the outer surface of said inner layer.

2. The process of rendering a flexible conductor moistureproof and retaining the flexibility thereof,.which consists in apply ing thereto an inner and an outer layer of fibrous insulating material,saturatingsaid outer layer with insulating compound, and

permeating only the outer surface of said inner layer with said compound. a

3. -The process of rendering a flexible conductor moisture roof and retaining the flexibility thereo which consists inapplying thereto a covering of fibrous insulating material and drawing such insulated conductor through a heated insulating com? pound at a rate of progression permitting the saturation of said insulating material to a depth less than the thickness thereof.

4. In a flexibletconducting cord, the combination of a conducting core, an inner and an outer layerof fibrous insulating material forming a covering therefor and an insulatingcompound saturating said outer layer and the outer surface of said inner layer.

5. In a flexible conducting cord, .the com bination of a conducting core,- a fibrous covering therefor, and an insulating compound saturating said fibrous covering to a depth less than the thickness thereof. p

In witness whereof, I, hereunto subscribe my name this 6th 1912. I

ALBERT PRUESSMAN. Witnesses:

. Tmwo. R. GEORGE,

day of February A. 1),, i 

